First Bosphorus Bridge



Place and date:

Istanbul – Turchia. 2015 – 2017


Design, supply, implementation and management of dynamic monitoring system on hanger system.



As part of the rehabilitation operations of the First Bosphorus Bridge, IHI provided for the replacement of the hanger system maintaining the traffic open on the bridge.

The bridge consists of 3 bays and has a light of the central span equal to 1090m. The hanging system consists of two 165m height antennas and a main cable and hanger system.

For the replacement of hangers and anchoring systems, a dynamic monitoring system has been provided for both anchoring systems and hangers.

Akron has taken care of the design, construction and supply phase up to the installation and management of the monitoring system.

The dimensions and the geometry of the work have led to a design of the plant with distributed geometry with 2 dynamic acquisition units with 64 channels on each tower connected by LAN; the connection for the synchronization of acquisitions between the two towers was carried out using a proprietary wireless network.

The system acquires data in continuous (h24) with a frequency equal to 100Hz for 20 hangers and related anchoring systems. Biaxial accelerometers have been installed for the hangers in order to determine the agent pull (vibrating string theorem – D’Alembert) while biaxial strain gage systems (Wheatstone bridge) with full bridges have been installed on the anchoring systems. Finally, the plant is completed by 8 temperature probes for the evaluation of thermal deformation corrections on the structure.

The data acquired allows the identification and dynamic monitoring of the effort parameters on anchors and hangers with such precision that it is possible to identify the passage of vehicles on the deck.

The system is entirely manageable remotely (via fiber optic and in backup via UMTS network).